Coated tools, such as cutting tools, have conventionally been known in which one or more of a titanium carbide layer, a titanium nitride layer, a titanium carbonitride layer, an aluminum oxide layer, a titanium aluminum nitride layer, or the like are deposited on a surface of a base body of cemented carbide, cermet, ceramics, or the like.
With the recent trend in higher efficiency of a cutting process, the cutting tools have a greater opportunity to be used for heavy intermittent cutting or the like, during which a large impact is exerted on a cutting edge. Under these severe cutting conditions, there is a demand for improving fracture resistance in order to inhibit chipping and peeling off of the coating layer due to the large impact exerted on the coating layer. There is also a demand for long time use by ensuring that the coating layer is less apt to wear.
Patent Documents 1 and 2 respectively disclose coated tools having an aluminum oxide layer deposited on a surface of a base body. Patent Document 1 discloses a coating layer. The coating film has cracks, and average crack interval in the aluminum oxide layer is made larger than average crack intervals in a titanium carbonitride film located thereunder. Patent Document 2 discloses an alumina film that is rich in κ-type aluminum oxide on the base body-side and is rich in α-type aluminum oxide on the surface-side of the aluminum oxide layer.